/**
*      author: Y_Yao
*      created: 2025-03-22 15:21:48
**/

#include<bits/stdc++.h>

#define int LL
using namespace std;
using LL = long long;
const LL LLINF = 9e18;
const int INF = 0x3f3f3f3f;
const int N = 1e4 + 7;
int fa[N],sz[N];
int n;

int find(int x)
{
    return fa[x] == x ? x : fa[x] = find(fa[x]);
}

void Union(int u,int v)
{
    u = find(u);
    v = find(v);
    if(u == v) return;
    if(sz[u] > sz[v]) swap(u,v);
    fa[u] = v;
    sz[v] += sz[u];
}

void solve()
{
   cin >> n;
   for(int i = 1;i <= n;i++)
   {
        fa[i] = i;
        sz[i] = 1;
   }
   for(int i = 1;i <= n;i++)
   {
        int x;
        cin >> x;
        Union(x,i);
   }
   int ans = 0;
   for(int i = 1;i <= n;i++)
   {
        if(find(i) == i) ans++;
   }
   cout << ans << endl;
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);

    int t = 1;
    // cin >> t;
    while(t--)
    {
        solve();
    }
    return 0;
}